I was very pleasantly surprised by this film!
I bought it out of curiosity but thoroughly enjoyed it. It's quite fast paced and half way through you really don't know who is a goodie and who is a baddie! It's a very British film with some wonderful British actors, set during WW2. John Mills is in his element as a RAF flier who gets shot down near the home of a secret Government scientist. Alistair Sim turns up and is wonderfully mysterious and I'm sure you'll enjoy watching a very young George Cole playing an evacuee who is involved in most of the story. It has spies, secrets, action, bravery, deception, romance - what more do you want? The scientists wife is delightfully eccentric which makes for plenty of confusion. If you enjoyed The Spy in Black with Conrad Veidt and Valerie Hobson, you'll enjoy this one too. It's a good fun spy film with a lovely sinister twist so typical of this sort of British film. I heartily recommend it.